In accordance with this invention, a method and apparatus for outdoor storage of agricultural products (silage, grain, etc.) and other materials to be stored (e.g., compost) produces such storage in large plastic bags, e.g., 4'-10' in diameter and 100'-200' in length. Filling the bag is accomplished with a bag filling machine or bagging machine. The machine includes a movable chassis, i.e., mounted on wheels, a tunnel mounted on the chassis, a hopper for receiving material and a rotor that forces the material from the hopper and into and through the tunnel from that end and out of the tunnel through the other end. A bag, e.g., having a 200' length, is gathered or folded in a manner to be mounted around the tunnel with an end closed and covering the exit end of the tunnel. Thus, material moved from the tunnel into the bag is deposited on the ground as the bag is filled. During the filling process, the movable machine moves forward and incremental portions of the bag are deployed from the tunnel.
A concern for the apparatus and process as described is the desire to fill the bag completely with the material. A loosely filled bag wastes storage space and increases cost. It is also more readily subject to tearing, e.g., under strong wind conditions, and depending on the material, the loosely filled bag can affect aeration and curing of the material being stored in the bag. Prior to the present invention, there were essentially three ways to obtain the desired complete filling of the bag. Initially a backstop was provided at the closed end of the bag with cables extending from the backstop to the bagging machine along each side of the bag. The cables were wound on rotatable drums. Brakes were provided on the drums. The brakes are pressure releasable and the pressure settings are adjustable. In operation the rotor forces the material into the tunnel and into the bag which is prevented from extending in length until the material is sufficiently compacted in the bag so that back pressure forces release of the drum brakes. The machine then rolls forward and the folded portion of the bag on the tunnel is deployed until the pressure is released whereupon the brake is reset. This cycle is repeated until the bag is totally filled.
It will also be noted that the machine's wheels have brakes that are also selectively used to provide resistance to forward movement of the machine. Such brakes by themselves are not sufficient as ground conditions can be wet, rough, sloped, etc. to alter the effectiveness of the wheel brakes. The exterior cables connected between the backstop and machine are effective but are somewhat dangerous and cumbersome. The cables and drums add extra cost (e.g., the cables are each in excess of 200' long and the drums must accommodate that length during site-to-site movement and at start up). The cables are under stress and if they should break, they can threaten the safety of persons standing near. Upon completion of a bag filling operation and before the machine can be moved to a new site and the filling operation continued, the cables have to be rewound onto the drums (a tedious and time consuming operation). (Examples of such exterior cable use are illustrated in U.S. Pat. No. 5,159,877.)
A more recent development is the precompaction of the material which take place inside the tunnel. A barrier is provided in the tunnel which inhibits flow from the tunnel into the bag. The barrier impedes flow primarily in the lower half of the tunnel, in the path of direct flow from the rotor, thus forcing the material to flow in large part up and over the barrier. The effect is that the tunnel is filled and the material is compacted before the material enters the bag resulting in the bag being substantially filled. Known barriers include gates, cables extended between the tunnel walls and flanges protruded from the tunnel walls or floor. Such barriers are exemplified by U.S. Pat. Nos. 5,860,271 and 5,671,594.